The subject application is related to subject matter disclosed in the Japanese Patent Applications No. Tokugan 2000-039683 filed in Feb. 17, 2000, and No. Tokugan 2000-297441 filed in Sep. 28, 2000 in Japan, to which the subject application claims priority under the Paris Convention and which is incorporated by reference herein.
1. Field of the Invention
The present invention relates to a chemical liquid processing apparatus for processing a substrate using chemical liquid and a chemical liquid processing method therewith and more particularly to technology for processing various types of substrates such as a semiconductor substrate in semiconductor device manufacturing process, reticule (photo mask) in lithographic process which is one step of semiconductor device manufacturing process, and flat panel in liquid crystal display manufacturing process.
2. Description of the Related Art
Generally, chemical liquid processing for processing various types of substrates using chemical liquid is carried out by performing chemical liquid film forming step for forming chemical liquid by puddling on a processing object substrate, on which a processing object film is formed, so as to process the processing object film into a desired configuration, and liquid removing (cleaning/drying) step for cleaning and drying the processing object substrate on which the chemical liquid is applied, repeatedly. Meanwhile, the chemical liquid processing step mentioned here includes, for example, development processing in photo-lithographic step of semiconductor manufacturing process, wet etching processing to be carried out after photo-lithographic step and the like.
By the way, the aforementioned chemical liquid film forming step and liquid removing (cleaning/drying) step have following technical problems which should be solved.
First, technical problems in the chemical liquid film forming step will be described.
The chemical liquid film forming step for etching the processing object film by coating and settling the chemical liquid on the processing object substrate, on which the processing object film is formed, has such a problem that supply of new etchant to an etching region is not accelerated because etching product remains on the etching region and the surrounding of the etching region. As a result of this problem, etching velocity around the etching region is reduced. This problem is particularly conspicuous around the etching region near a broader etching region.
To solve this problem, some applications were proposed up to now. For example, Japanese Patent Application Laid-Open No. H11-329960 has disclosed a technology of moving chemical liquid on the processing object film at the time of etching. According to this document, a predetermined sheet material is brought into contact with the surface of chemical liquid on the processing object film and by moving that sheet material, the chemical liquid is moved on the processing object film. By moving the chemical liquid on the processing object film, a flow is generated in the chemical liquid so that the chemical liquid is agitated. As a result, new etchant is supplied to the etching region, thereby making it possible to suppress reduction of the etching velocity in the etching region near a broader etching region.
However, if such technology is employed, after the chemical liquid is agitated, the sheet material needs to be washed and when washing the sheet material, dust and dirt adhering to the sheet material adhere to the surface of the processing object substrate, so that a defect may occur on the processing object substrate.
On the other hand, according to other proposal, the chemical liquid is moved on the processing object film by rotating the processing object substrate intermittently (see Japanese Patent Application Laid-Open No. H11-307433). According to this technology, the processing object substrate is held by the substrate holding portion and by repeating a rotation and a static condition of the processing object substrate, the chemical liquid is moved.
However, as a result of investigation of this technology by inventors of the present invention, when the processing object substrate was rotated, the chemical liquid was not moved but rotated together with the processing object substrate because of its viscosity. And, when the rotation of the processing object substrate was stopped, the chemical liquid only trembles slightly due to its inertial force. Therefore, even if this technology is employed, the reduction of etching velocity in the etching region near a broader etching region must be difficult to suppress sufficiently.
As described above, the conventional chemical liquid film forming step cannot suppress the reduction of etching velocity in the etching region without generation of defects or additional work. Thus, the yield rate of the entire chemical liquid processing cannot be improved.
Next, technical problem of liquid removing (cleaning/drying) step will be described.
In a conventional liquid removing (cleaning/drying) step, cleaning chemical liquid on the substrate is blown out and removed by rotating the substrate at high speeds.
However, when the liquid removing (cleaning/drying) step is carried out by this method, the quantity of defects induced by microscopic dust generated from abrasion between a chuck for fixing the substrate and a rear face of the substrate is increased with decrease of pattern dimension and increase of rotation speed. Further, because of increases of aspect ratio of resist pattern and diameter of the substrate with micro-fabricated resist pattern in recent years, influences by water flow and centrifugal force generated at high speed rotation increase, so that pattern fall is more likely to occur. Thus, in the conventional liquid removing (cleaning/drying) step, the yield rate of the entire chemical liquid processing cannot be improved like the chemical liquid film forming step.
As described above, the conventional chemical liquid processing apparatus and chemical liquid processing method have technical problems which should be solved early in both the chemical liquid film forming step and liquid removing (cleaning/drying) step. Thus, it is difficult to improve the yield rate of the entire chemical liquid processing.
The present invention has been achieved to solve the above described technical problems and its object is to provide a chemical liquid processing apparatus capable of improving the yield rate of chemical liquid processing.
Another object of the present invention is to provide a chemical liquid processing method capable of improving the yield rate of the chemical liquid processing.
According to a first feature of the chemical liquid processing apparatus and the chemical liquid processing method, there are included at least the steps of: supplying chemical liquid for processing a processing object film to a processing object substrate, on which the processing object film is formed, so as to form chemical liquid film on the processing object substrate; and after the step for forming the chemical liquid film, forming air flow such that it makes a contact with the chemical liquid film so as to hold the chemical liquid film on the processing object substrate and form a flow of the chemical liquid on the surface of the chemical liquid film.
According to this chemical liquid processing apparatus and chemical liquid processing method, the chemical liquid is moved by forming airflow above the chemical liquid film and making the air flow into contact with the surface of the chemical liquid. By this procedure, the chemical liquid is agitated, thereby improving uniformity of processing the processing object film by the chemical liquid. In the present invention, the steps of forming chemical liquid film on the processing object substrate and forming the flow of chemical liquid on the chemical liquid film is defined as chemical liquid film forming/agitating process.
Further, the second feature of the chemical liquid processing apparatus and chemical liquid processing method according to the present invention is that, a process for removing liquid supplied beforehand to a substrate comprising the steps of: holding said substrate; rotating a plate having an air intake hole above said substrate; generating a negative pressure between the plate and a processing object substrate by rotating said plate; and generating air flow between said processing object substrate and said plate by sucking air through said air intake hole in the presence of the negative pressure.
According to this chemical liquid processing apparatus and chemical liquid processing method, the liquid on the substrate can be removed without rotating the substrate. And further, the occurrence of fall of resist pattern, which occur from the effect of a centrifugal force and water flow generated in the case of removing liquid by rotating a substrate, can be reduced. Further more, by not-rotating the substrate, generation of dust from the rear face due to abrasion between the substrate and the chuck could be prevented.
Further, according to a third feature of the chemical liquid processing apparatus and the chemical liquid processing method, there are included the steps of:
supplying chemical liquid for processing a processing object film to a processing object substrate on which said processing object film is formed so as to form chemical liquid film on said processing object substrate; after the step for forming the chemical liquid film, forming air flow which contacts with the chemical liquid film so as to hold said chemical liquid film on said processing object substrate and form a flow of the chemical liquid on the surface of said chemical liquid film using a plate disposed above said processing object substrate and having an air intake hole with the valve at the center; and
removing said chemical liquid supplied to a substrate, wherein the step for removing said chemical liquid supplied to a substrate further comprises the steps of: generating a negative pressure between the plate and said processing object substrate by rotating said plate; and generating air flow between said processing object substrate and said plate by sucking air through said air intake hole in the presence of the negative pressure.
According to this chemical liquid processing apparatus and chemical liquid processing method, by performing the successive process of agitating the chemical liquid film on the processing object substrate, rinsing the processing object substrate surface and removing the chemical liquid film using the plate, it is possible to (1) improve the uniformity of the processing the processing object substrate by chemical liquid, (2) reduce the occurrence of fall of resist pattern, which occur from the effect of a cetrifugal force and water flow generated in the case of removing liquid by rotating a substrate, and (3) prevent the generation of dust from the rear face due to abrasion between the substrate and the chuck. As a result, the yield rate of the entire chemical liquid processing can be improved.